Machine for needling fabrics

ABSTRACT

A method of needling a web of fibrous material in which the web is advanced along a feed path relative to an array of needles which repeatedly penetrate the web. The relative longitudinal feed movement which takes place between penetrations by the needle array is varied so that preferably each successive feed step differs in magnitude from the preceding one. One embodiment of apparatus for performing the method includes feed means for advancing the web along the feed path and incorporating a transmission mechanism including a dimensionally variable component, variation of the dimension of said component varying the magnitude of the feed step of the web between successive penetrations. A further embodiment of the apparatus includes a transmission mechanism incorporating a differential gear to convert a continuous uniform rotation into a continuous nonuniform rotation.

United States Patent Primary ExaminerLouis K. Rimrodt [151 3,681,822 Sanders 1 Aug. 8, 1972 [54] MACHINE FOR NEEDLING FABRICS Attorney-Friedman & Goodman [72] Inventor: Norman Thomas Sanders Studle England y, 571 ABSTRACT Eadie A method of needling a web of fibrous material in [73] A sslgnee' N Industries Limited which the web is advanced along a feed path relative [22] Filed: May 26, 1970 to an array of needles which repeatedly penetrate the web. The relative longitudinal feed movement which A 40484 takes place between penetrations by the needle array is varied so that preferably each successive feed step [52] us. Cl. ..28/4 R fers n magn ude from the preceding one. One em- [51] Int. Cl. ..D04h 18/00 bodiment of apparatus for performing he me h in- [58] Field of Search ..2s/4 R, 72.2 eludes feed means for advancing the web along the feed path and incorporating a transmission mechanism 5 References Cited including a dimensionally variable component, variation of the dimension of said component varying the UNITED STATES PATENTS magnitude of the feed step of the web between successive penetrations. A further embodiment of the ap- 2 g paratus includes a transmission mechanism incor- 29l5804 12 1959 f; ermot 4 R porating a difl'erential gear to convert a continuous l 6534 J 6 4 32: 4 R uniform rotation into a continuous non-uniform rotation.

4 Claims, 8 Drawing Figures P-ATENTEDA B 8 I973 SHEET 1 [IF 4 PATENTEU 8'97? 3.681.822 SHEET no? a 1 MACHINE FOR NEEDLING FABRICS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a method of needling a web of fibrous material wherein the web is subjected to repeated penetration by an array of needles at positions spaced apart both longitudinally and transversely of the web, and of a feed path along which relative advancement is effected between the web and the array of needles. Such method is hereinafter referred to as being of the kind specified.

The invention also relates to a needling machine for carrying out the method of the kind specified and comprising a body or supporting structure affording a feed path of a web of fibrous material to be subjected to needling, an array of needles spaced apart both longitudinally and transversely of the feed path and supported from said body or supporting structure for movement in a direction to enable the needles to penetrate the web, operating means for effecting said movement of said array of needles, and feed means for effecting advancement of the web along the feed path.

2. Description of the Prior Art In the performance of a method of needling of the kind specified and in a needling machine for this purpose, the utilization of an array of needles, which are spaced apart both longitudinally and transversely of the feed path and consisting, for example, of a plurality of transversely extending rows of needles in which the needles in each row are spaced apart transversely of the feed path and the rows themselves are spaced apart longitudinally of the feed path, is adopted to enable the web to be penetrated by the needles at a very large number of positions situated very close to each other, closer in fact that would be possible were all the needles to be situated in a single transversely extending row. This close spacing of the positions at which the web is penetrated is an essential for the production of certain kinds of felted fabric composed of a mass of closely packed intertangled fibers.

Heretofore the method has suffered from two major weaknesses.

Firstly, although the nominal or intended positions of the needles have been carefully determined in order that a correct and equal amount of punching takes place per unit width of the web, there has been failure to take into account the fact that barbed needles will not always be consistently straight along their lengths, but may be bent in manufacture to different degrees or become bent in the course of their working life and, further, the method of mounting them e.g. in a needle board, may itself lead to positional inaccuracy at the point of the needle (it being the disposition of the point which substantially governs the position of penetration into the web).

Secondly, it will be apparent from the foregoing that while only a single needle may theoretically be at work in a particular longitudinal narrow zone (herein for convenience referred to as a line) of the web, a situation is likely to, and in practice does, arise, due to the faults mentioned, wherein more than one needle will be effectively at work in a single longitudinal line.

In such cases there will typically be a distance (longitudinally of the direction of feed of the web) between these two needles which may be as great as the corresponding dimension of the board, say 10 inches, or as little as the centers between the rows of needles, say one-half inch. Further, there maybe considerably more than two such needles at work at spaced apart positions along such a longitudinal line, perhaps as many as four or five.

Webs are in some cases fed through a machine of the kind specified with an intermittent feed, the feed mo tion taking place when the point of the needle has been drawn clear of the web. The distance travelled by the web in each increment of feed is constant and may lie between, say, one-eighth'inch and, say, one-half inch.

Therefore, any needle operating in a longitudinal line of the web may well, as the web proceeds through the machine, punch into a hole made by another of the needles operative in that line (repeat punching) or close to such a hole (over-needling) when the distance between any two needles is exactly divisible by the unit of feed. The more needles there are which may be considered for this purpose to be operating in a particular line of the longitudinal feed of the web, the greater the chance of repeat punching and/or over-needling takingthis deficiency/surfeit leadsto a heightening of the difference in appearance and texture (with possible change in the mechanical strength or properties) between one line and another.

Where there is repeat punching one line will have a deficiency and will not only be under-needled but less likely to suffer from repeat punching from the needles of adjoining lines as the chance of that happening is reduced in mathematical proportion. This factor again heightens the difference between adjacent lines in the respects already mentioned.

The effects of repeat punching are that if a position on the web is exactly repeat punched, very little if any extra work will be done to the web at that position and the needle which does the repeat punching may in some circumstance be considered as non-operating, so that this needle which through imperfect mounting or bending has subtracted itself from one line has not effectively added itself to another.

Further, in over-needling (i.e. near repeat punching) the needle does, over a very small :area, do a very great amount of extra work (possibly double the amount or more). If, as is quite possible, a third or fourth needle should punch in close proximity, it will result in a serious fault relative to the whole theory of the needle felting method which is one of a vast number of precisely aimed penetrations so calculated and engineered as to do precisely the correct and equal amount of work over each unit area.

Inter alia this influences the way in which the felt reacts in subsequent processes of thermal bonding, filling, brushing or backing.

In the needle array, as has been proposed, is moved relative to the web, transversely of the feed path of the web in alternate directions inbetween needle penetrations, proper increments of movement of the web will convert what could have been a straight line fault to a fault manifested by a wavelike line. This is particularly the case where the fault is due to over-needling by two, three or fourneedles that are in close proximity to one another, and such wavelike lines will still be visually prominent and will still affect the mechanical properties of the needled material.

SUMMARY OF THE INVENTION According to the invention a method of the kind specified of needling a web is characterized in that the magnitude of the relative longitudinal feed, which takes place between the needle array and the web inbetween penetrations of the needle array into the web, is varied throughout the performance of the method.

It will be understood that the variation may be continuous or discontinuous in nature.

The feed movement imparted to the web relatively to the needle array may be intermittent and comprise a succession of discrete feed steps during the periods during which the needle array is withdrawn from penetrating relation with the web. In this case the magnitude of the'feed step imparted to the web inbetween each successive penetration of the web by the needle array may be varied so that each feed step differs in magnitude from the preceding one.

Also, but not essentially, the rate of change of magnitude of the feed step may be varied. If the rate of change represented graphically against time is a cyclic function then the period of the cycle would be made large enough to ensure that a substantial length of the web will have moved past the needle array before the cycle repeats. By a substantial length of the web, is meant a length of the order of at least half the length of the needle array as measured in the direction of feed of the web.

When the magnitude of web feed taking place between needle penetrations of the web is altered by even a small amount, it will significantly change the probabilities of the needles operating in a particular longitudinal line from repeat punching and overneedling. However, at the same time it is likely that the small change in the web feed will bring other needles in another line, which, by their disposition, may not have been repeat punching or over-needling, into such a relationship. The overall effect, however, will be to scatter the repeat punching and over-needling faults so that, while these faults are not eliminated, they will not occur at positions such that they present a distinct fault line, e.g. in visual terms a straight or wavy trarnline effeet.

The period of the cycle and the form thereof will be such that the different increments of feed are collectively completed over such number of needle penetrations as will best diffuse the repeat punching and/or over-needling effect. This would normally be expected to take place in less than the number of needle penetrations that take place while the web traverses from the intake to the exist side of the needle array and probably in about half of that number.

It is also possible to apply the invention to the performance of a method of needling of the kind specified wherein the web is moved continuously, as distinct from intermittently, and in this case the rate of feed movement would also be varied, preferably continuously. Again, if the speed of the web plotted as a graphical function against time is represented by a cyclic curve, then the period of such curve would be made great enough to ensure passage of a substantial length of the web past the needle array before a repeat takes place.

The invention further resides in the provision of a needling machine of the kind specified for carrying our the method wherein the feed means for effecting advancement of the web includes a device for effecting variation in the magnitude of the feed movement imparted to the web between successive penetrations thereof by the needle array.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described, by way of example, with reference to the accompanying drawings wherein:

FIG. 1 is a view in side elevation of a portion of a transmission mechanism which may be incorporated in a needling machine of the kind specified for carrying out the invention;

FIG. 2 is a fragmentary view illustrating a modification of the manner of mounting the two parts of the connecting rod seen in FIG. 1 for relative movement to permit of variation of the effective length of the connecting rod;

FIG. 3 is a diagrammatic view illustrating an alternative arrangement wherein a connecting rod or link incorporates a piston and cylinder assembly for varying the effective length;

FIG. 4 is a view similar to FIG. 3 illustrating an alternative arrangement also using a piston and cylinder assembly as part of a connecting rod or link.

FIG. 5 is a diagrammatic illustration of a differential gear device which may be incorporated in a transmission mechanism which enables the web to be fed continuously through a needling machine.

FIG. 6 is a reproduction (Photographic) of a pattern of holes punched by an array of needles of a machine of the kind specified not incorporating the present invention;

FIG. 7 is a similar reproduction of the machine modified to incorporate one embodiment of the invention, and,

FIG. 8 is a diagrammatic illustration of a needling machine'to which the invention can be applied.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring firstly to FIG. 8, the needling machine may be of any suitable construction comprising, for example, a body or supporting structure A including a bed or table B defining a feed path F and furnished at its forward edge with a laterally extending horizontal take-up roller C acting as the web-engaging member of the feed means, and above which bed or table is mounted a vertically reciprocating slide or ram D adapted to carry a needle board E.

In the needle board E an array of needles is arranged in laterally extending rows with the needles in each rwo spaced apart laterally from each other and the various rows spaced apart longitudinally from each other. For needles which are not bent and are correctly positioned, the positions of the needles are ideally such that for a given penetration by the array of needles only one needle penetrates the web along any given logitudinally' extending line parallel to the length of the web.

The slide or ram may be driven from a crank shaft extending laterally of the machine between upstanding side frame portions and driven from a suitable motor such as an electric motor T.

The take-up roller C is driven intermittently and unidirectionally from a drive shaft H rotating in synchronism with the crank shaft, or directly from the latter, through the intermediary of a crank, cam or eccentric 11 on the crankshaft or driving shaft, a connecting rod R joining said crank, cam or eccentric 11 to the oscillatory arm P of a one-way clutch device N, the output element S of which drives the take-up roller C. The arrangement thus so far described is conventional and is therefore not illustrated.

In place of the fixed length connecting rod R or- 'dinarily provided as shown in FIG. 1, that illustrated in FIG. 1 is substituted.

This connecting rod in accordance with the invention comprises two parts, of which is connected to e the eccentric 11 about an axis 12 offset radially from the rotational axis 13 of the eccentric by a distance R1.

The other part 14 of the connecting rod is pivotally connected at its lower end (not shown) to the oscillatory arm P of the pawl and ratchet or one-way clutch device N previously mentioned. The two parts 10 and 14 are hingedly coupled to each other by a pin 15 extending through hinge portions 16 and 17 on these parts with the axis of the pin 15 offset laterally from the center line of the parts 10 and 11 whereby these form an obtuse angled elbow structure.

Rigid with the part 10 is a mounting member 18 extending to the side of the part 10 remote from the pin 15, and on this is mounted a cam 19 rotatable about an axis 20.

The cam is adapted to be rotated intermittently and uni-directionally by a pawl and ratchet mechanism whereof the ratchet 21 is fast with the cam 19, and the pawl 22 is mounted on an oscillatory arm 23 which is oscillated by a connecting rod 24. A holding pawl 25 is provided on the mounting member 18 to prevent reversed rotation of the cam while permitting it to rotate in the direction of the arrow 26.

The rod 24 is moved longitudinally relatively to the part 10 of the main connecting rod by virtue of pivotal connection to a pin 27 spaced radially from the axis 13 by a distance R2 which is less than R1.

The cam 19 bears at its periphery on a follower 28 formed as a rigid extension of the hinge part 17 on the connecting rod part 14, and as the rotational position of the cam changes so also does the obtuse angle between the parts 10 and 14 of the main connecting rod, thereby varying the effective length of the latter.

By varying the effective length of the main connect ing rod, the magnitude of each successive intermittent feed step imparted to the take-up roller is changed relative to the preceding one and this is effective to avoid or reduce the incidence of defects of the character previously mentioned.

In an alternative arrangement, as shown in FIG. 2 wherein like parts are designated by reference numerals with the prefix 1, the upper part of the main connecting rod is assembled with the lower part 1 14 for endwise translatory movement between the parts instead of hinging movement. For this purpose the mounting member 118 includes guide pins 118a engaging in guide openings in the follower part 128. As before the parts 118 and 128 are adjustable towards and away from each other by rotation of a cam arranged in the same manner as the cam 19 of FIG. 1 but for simplicity not shown in FIG. 2.

Suitable means, for example tensionsprings, could be provided if necessary for urging the parts 10, 14 and 110, 114 relatively towards each other in a direction to maintain contact between the periphery of the cam and the follower part 28 and 128 as the case may be.

The arrangements shown in FIGS. 1 and 2 provide for stepwise variation of the magnitude of each successive feed step of an intermittently advance web.

Referring now to FIG. 3 which shows a further alternative mechanism, in this case the two parts of the connecting rod would be fixed respectively to the piston rod 31 of a piston and cylinder assembly 30, and to the cylinder 32 thereof, so that the effective length of the connecting rod can be changed according to the quantity of fluid under pressure, for example hydraulic fluid, admitted to either of the spaces 34 and 35 above and below the piston 36.

The space 34 is thus connected to one end of a master cylinder 37 by a pipe 38, while the space 35 is connected by a pipe 39 to the other end of the master cylinder 37.

A piston 43 is the master cylinder 37 is reciprocated from a driving member such as a crank 40 coupled to a motor, such as an electric motor, through the intermediary of a gear box. A reservoir chamber 41 is pro vided to maintain the system, comprising the two cylinders 37 and 32 and pipes 38 and 39, full of hydraulic fluid, a suitable one-way valve being provided, for example, in the pipe 42, permitting fluid to flow into the system but preventing outflow (except when a predetermined internal pressure in the cylinder and pipe system is exceeded).

This arrangement, by virtue of continuous rotation of the crank 40, continuously adjusts the effective length of the connecting rod and hence the magnitude of each successive feed step will be different from the preceding step.

In the alternative arrangement illustrated in FIG. 4 parts corresponding to those shown in FIG. 3 are designated by like numerals of reference with the prefix In this arrangement the piston 143, instead of being reciprocated from a crank driven by a motor, is coupled to a driving cylinder 144 supplied from a pump 145 through pipes 146 and 147 containing change-over valves 148, 149, so that at any given time one of these pipes is connected to the pressure outlet of the pump and the other to the exhaust through pipes 150a, 15% and 151a, 151b.

Change-over of the valves of 1417, 148 is effected by means of an actuating element 152 on a rod 153 coupling piston 143 with piston 154 in the driving cylinder 144.

Whereas the arrangement illustrated in FIG. 3 will provide cyclic variation in the rate of feed of the web in accordance with a simple harmonic characteristic curve (velocity of feed being plotted against time), the system shown in FIG. 4 will provide a symmetrical saw tooth-shaped characteristic.

While the arrangement shown in FIGS. 1 to 4 has been described in relation to a take-up roller C which is driven intermittently, it will be understood that these arrangements are equally applicable to a connecting rod R in a transmission mechanism for. rotating the take-up roller C continuously. In this case, the connecting rod R would simply be connected between the takeup roller C and a continuously rotated crank, cam or eccentric such as 11 on the crankshaft or driving shaft.

However, more conveniently, in a machine of the kind specified wherein the take-up roller C is rotated continuously to advance the web steplessly, the rate of advancement of the web can be varied cyclicly by driving the take-up roller C from the motor T through a transmission mechanism as shown at G in FIG. 8. This mechanism incorporates a differential gear having a first continuously rotating input element driven from the motor or driving member, a second input element which is oscillated backwards and forwards, and an output member which drives the take-up roller continuously but at a cyclicly varying rate. One suitable arrangement is illustrated in FIG. 5. In this Figure, the

, differential gear 50 is of the specific type and includes an input shaft 51 which is continuously rotated at a uniform rate and carries a sun gear 52. The sun gear 52 meshes with planet gears '53 rotatably mounted on a planet carrier 54 secured to an output shaft 55 which is arranged co-axially with the input shaft 51. The planet gears 53 mesh with a toothed annulus 56 which is adapted to be oscillated backwards and forwards by means of a connecting rod 57 which is pivotally con nected at one end to a flange 58 carried by the annulus 56, and is pivotally connected at its opposite end to an eccentric 59 carried by a continuously rotating input shaft 60. The shaft 51 and 60 may be gearedto one another so that as the input shaft 51 is rotated continuously at a uniform rate, the annulus 56 is oscillated continuously so that the rate of rotation of the output shaft 56 varies cyclicly and continuously.

In order to provide for variation of the rate at which rotation of the putput shaft 55 is varied, the input shafts 51 and 60 may be interconnected by variable gearing, or they may be driven from separate independent motors.

A comparison of FIGS. 6 and 7 will show the improvement brought about the scattering of repeat punching and over-needling faults produced in accordance with the invention. It will be noted that in FIG. 6 the fault lines discernable are much more pronounced than in FIG. 7. In particular a line indicated at X, extending along the left-hand margin of FIG. 6 consists of a series of identical groups of very closely spaced holes evidently formed by an overneedling fault with substantial intervening areas where there has been no penetration at all. In contrast the corresponding line, indicated at Y, in FIG. 7 shows difusion of the concentrated groups of penetrations and considerable changes along the length of the line in the configuration presented by the groups of penetrations,

whereas such configuration is constant along the whole length of the line in FIG. 6. Similar phenomena can be observed on the other lines in these Figures.

In FIG. 7 the overall cycle time for the cyclic variation of feed step was equivalent to that occupied by fifty penetrations of the web by the needle array. The mean value of the feed step was 0.150 inches and the magnitude of the feed step varied in equal increments up to 0.025 inches above and below the mean value.

Iclaim: I

l. A needling machine comprising a. a body affording a feed path for the web of fibrous material to be subject to needling,

b. an array of needles spaced apart both longitudinally and transversely of the feed path and supported from said body for movement in a direction to enable the needles to penetrate the web,

c. operating means for effecting said movement of the array of needles,

d. feed means for effecting advancement of the web along the feed path,

e. drive means for driving said feed means and said operating means f. first transmission means for transmitting drive to said operating means from said drive means g. second, variable transmission means for transmitting drive from said drive means to said feed means adjustment means operatively associated with said variable transmission means for effecting variation of the magnitude of the feed step of the web relative to the needle array between successive penetrations of the web by the needle array, said adjustment means being drivingly associated with said drive means so as to be driven therefrom, whereby the magnitude of said feed step is auto- 'matically varied throughout a period of operation of the machine 2. A machine as claimed in claim 1 wherein a. the feed means includes a rotary web engaging member,

b. said drive means includes a rotary driving member c. said variable transmission means includes a link having a variable dimension, and

d. the adjustment means is arranged to vary said dimension of the link and thereby vary the instantaneous position of the rotary web engaging member relative to the instantaneous position of the driving member.

3. A machine as claimed in claim 2 wherein said link comprises a connecting rod having two relatively adjustable parts and said adjustment means is arranged to adjust the relative positions of said parts.

4. A machine as claimed in claim 1 wherein a. the feed means includes a rotary web engaging member,

b. the drive means includes a rotary driving member c. the adjustment means comprises a differential gear incorporated in said variable transmission means and having a first continuously rotating input element driven from said rotary driving member, a second input element which is oscillated backwards and forwards, and an output element which drives said rotary web engaging member at a cyclically varying rate. 

1. A needling machine comprising a. a body affording a feed path for the web of fibrous material to be subject to needling, b. an array of needles spaced apart both longitudinally and transversely of the feed path and supported from said body for movement in a direction to enable the needles to penetrate the web, c. operating means for effecting said movement of the array of needles, d. feed means for effecting advancement of the web along the feed path, e. drive means for driving said feed means and said operating means f. first transmission means for transmitting drive to said operating means from said drive means g. second, variable transmission means for transmitting drive from said drive means to said feed means h. adjustment means operatively associated with said variable transmission means for effecting variation of the magnitude of the feed step of the web relative to the needle array between successive penetrations of the web by the needle array, said adjustment means being drivingly associated with said drive means so as to be driven therefrom, whereby the magnitude of said feed step is automatically varied throughout a period of operation of the machine
 2. A machine as claimed in claim 1 wherein a. the feed means includes a rotary web engaging member, b. said drive means includes a rotary driving member c. said variable transmission means includes a link having a variable dimension, and d. the adjustment means is arranged to vary said dimension of the link and thereby vary the instantaneous position of the rotary web engaging member relative to the instantaneous position of the driving member.
 3. A machine as claimed in claim 2 wherein said link comprises a connecting rod having two relatively adjustable parts and said adjustment means is arranged to adjust the relative positions of said parts.
 4. A machine as claimed in claim 1 wherein a. the feed means includes a rotary web engaging member, b. the drive means includes a rotary driving member c. the adjustment means comprises a differential gear incorporated in said variable transmission means and having a first continuously rotating input element driven from said rotary driving member, a second input element which is oscillated backwards and forwards, and an output element which drives said rotary web engaging member at a cyclically varying rate. 